excessive oil consuption

[kiwi]

Hi me again,smokey gt750j,took bike for a long run,about 190ml nearly run out of 2 stroke oil,costing more for oil than petrol.gas mileage is good but chewing thru the Silkoline comp2 at about a pint every 100ml,pump arm is all set up right and not loosing any when sitting so any ideas why so thirsty on the slippery stuff, and only cruising around 60-65mph,are new pumps available,or as its obviously going thru the engine just keep leaning it out keeping an eye on the plugs,your experience appreciated
Thanks Dennis

[yeadon_m]

Dennis, yes, you are massively over using oil. I get 500+ miles per litre I think under similar riding.
I would check whether the pump arm is on wrong way around. The pump should put out masses more oil with the arm fully open but if the arm is upside down it'll over deliver all the time except wide open. I had a 550A like this and it was revolutionised by checking and fixing a silly fault a PO must have introduced.
Cheers, Mike

[kiwi]

pump arm seems to be ok,looks the sames as any photos ive seen so dont think thats the issue,but ill recheck thanks

[Suzsmokeyallan]

The arm looks the same in either position, its the orientation of the inner part of the shaft you cant see thats different. Remove the arm, turn the shaft 180 degrees and then put the arm back on.

[Suzukidave]

To check the pump arm position remove the pump off the engine , when you move the arm to full output the drive shaft in the bottom will move up into the pump body a bit . If it moves down the arm is on 180 degs out . If you havent removed these pumps before watch out for the drive pin that can slide out of the pump drive shaft .

[kiwi]

hi,sounds like this could be the problem,not to mechanically minded,so do you just remove nut holding control arm,remove bolt,is there a shaft inside the pump that you can then access to turn 180d,
thanks

[Suzukidave]

Yep , thats about it .. remove the nut , arm and return spring turn the flat sided shaft 1/2 turn and reassemble . it would be good to check this is indeed the problem as the plungers in the pump can also get stuck http://www.pinkpossum.com/GT750/Oilpump.htm" onclick="window.open(this.href);return false;

[kiwi]

hi guys,that would have been to easy,tried it out today ,went for a ride still hogging the oil probably worse if anything,where does that leave me,piston in fuel pump stuck maybe,didnt really want to take that off but looks like ill have to ,anything esle it could be
thanks dennis

[Suzukidave]

The pump is the only thing that comes to mind that could be the cause , if you dont have a replacement pump and want to rework yours GTReiner has the replacement gasket if you mess yours up opening it up . Did you happen to run the bike without the side cover on the pump cover to see if it wasnt hanging up or anything .

[kiwi]

yes run it without cover on ,its not sticking at all so whats involved in reworking existing pump
dennis

[Suzukidave]

Richard's site covers the oil pump pretty good showing whats inside http://www.pinkpossum.com/GT750/Oilpump.htm" onclick="window.open(this.href);return false;

[tz375]

A quickie test is remove the right frame cover and see where the oil level is. Mark it with a sharpie. Leave for a couple of days and see if the level has dropped.

Dropping oil level is indicative of a check valve leaking down.

[kiwi]

definitly not leaking oil thru valves while sitting so guese ill have to bite the bullet and take pump off,are these available new or reconditioned anywhere
thanks dennis

[Suzsmokeyallan]

Theres not much to the pump in terms of parts or complexity. Richards site has some good pics showing how it all works.
You will need to order a top cover gasket from GTreiner as well as be prepared to disassemble the pump to check the plungers.
New pumps are hardly ever available and if they are the price is high for nos ones, so most replacements will be used and or needing to be overhauled.

[kiwi]

ok, thanks for all the info,guess ill pull it off and see what i can find
dennis